For the first time in history, a judge has granted a writ of habeas corpus on behalf of a nonhuman animal.

This afternoon, in a case brought by the Nonhuman Rights Project (NhRP), Manhattan Supreme Court Justice Barbara Jaffe issued the writ on behalf of two chimpanzees, Hercules and Leo, who are being used for biomedical experimentation at Stony Brook University on Long Island, New York.

Under the law of New York State, only a “legal person” may have a writ of habeas corpus issued in his or her behalf. The Court has therefore implicitly determined that Hercules and Leo are “persons”.

To be clear, this does not mean that the two chimpanzees will immediately be set free. A common law writ of habeas corpus involves a two-step process:

First, a judge issues the writ of habeas corpus, which requires Stony Brook University to appear in court and provide a legally sufficient reason for detaining Hercules and Leo. The university is being represented by the Attorney General of New York.

Then, in the second step, the Court will determine whether the reason given by Stony Brook is legally sufficient to keep holding the chimpanzees captive, or whether they should be freed.

The NhRP has asked that Hercules and Leo be released into the care of Save the Chimps, a sanctuary in Ft. Pierce, Florida. There they will spend the rest of their lives primarily on one of 13 artificial islands on a large lake in Ft. Pierce, Florida, along with 250 other chimpanzees in an environment as close to that of their natural home in Africa as can be found in North America.

Whatever happens in the second step of this process, Judge Jaffe’s ruling has begun to dismantle the arbitrary legal barrier that separates all humans from all other kinds of animals. The ruling implicitly affirms that your right to have your day in court does not depend on what species you are, any more than it depends your skin color or your gender. Rather, it depends on the degree of autonomy and self-determination you exhibit.

It also affirms that being a “legal person” is not the same thing as being a human being. Legal personhood means that an entity counts in civil law. There are many examples of legal persons that are not human beings, including corporations.

Hercules and Leo’s suit was originally filed in the Supreme Court of Suffolk County in December, 2013. A Justice of that Court refused to issue the requested writ of habeas corpus. An appeals court then ruled that the NhRP lacked the right to appeal. But in the belief that both courts had erred, the Nonhuman Rights Project re-filed its petition in the New York County Supreme Court in Manhattan, which led to today’s decision.

In two similar cases on behalf of two other chimpanzees, Tommy and Kiko, the Nonhuman Rights Project has filed Motions for Leave to Appeal to New York’s highest court, the Court of Appeals. Decisions in both cases are pending.